238 POWER AND THE PLOW 



traction power are far too widely separated. No one has ever 

 asked a single horse to be an efficient draft animal and a swift- 

 going roadster at the same time. Even on the farm the pro- 

 prietor recognizes the difference in type, and usually keeps 

 one or more horses almost solely for driving, though avail- 

 able for auxiliary power in tne field if needed. Why not 

 then look forward to the time when the power require- 

 ments of the farm shall have been divided into two classes, the 

 heavy and the light; when farm operations and farm imple- 

 ments shall have been standardized as to power requirements, 

 so that two tractors one heavy and powerful, the other, 

 light and nimble shall be able to find practically uniform 

 loads in all kinds of work? 



The admitted limitations to the small tractor's range of 

 efficiency may lead to the development of combination machines, 

 where animals provide the tractive force and motors the work- 

 ing power, especially for small operators. For ordinary enter- 

 prises the saving in time and human labor, with the gain in 

 simplicity, make the direct traction system much to be pre- 

 ferred. Perhaps an improvement in direct tractors might be 

 effected by developing auxiliary motors to be used only in 

 ascending grades. This is already done in California with steam 

 tractors, the auxiliary motors on heavy logging wagons being 

 supplied with steam from the tractor. Similarly, road trains 

 have been equipped in Europe with a flexible-jointed shaft, 

 transmitting power from a single engine to the wheels of each 

 wagon. In many cases it is a question of traction i. e. f 

 foothold, rather than of engine power, and these methods 

 greatly increase the grip on the ground. 



Some of the ideas and inventions of the various schools of 

 power enthusiasts are not without merit, and under future 

 conditions may have real commercial value. The rotary prin- 

 ciple exercises a peculiar grip on the minds of the inventors, 

 owing, perhaps, to the rapidity and completeness of the results 

 which it may bring about. The plow, however, has best con- 



